Pneumatic control apparatus



March 28, 1950 MOORE 2,501,957

1 PNEUMATIC CONTROL APPARATUS Filed Dec. 22. 1945 I I I I I I I I I I Il I I I J i U v v v 'J'IIIL'IIIIIIIIII A A A a INVENTOR.

ITTOk/VEY C'OLA-MA/V J 15/00/05 Patented Mar. 28, 1950 PNEUMATICcoN'rnoL ArrsnA'rUs Coleman B. Moore, Carroll Park, Pa., asslznor 'toMoore Products Co., Philadelphia, Pa., a on partnership ApplicationDecember 22, 1945, Serial No.- 637,057

8 Claims. (Cl. 137-153) This invention relates to pneumatic controlapparatus and more particularly relates to structure for controlling thebleeding or exhaust of fluid from such apparatus.

The invention further relates to an improved diaphragm construction foruse in pneumatic control apparatus.

It has heretofore been proposed to employ a pneumatic circuit in which aplurality of diaphragm elements were separated and mounted to provide achamber, the diaphragm's being mechanically connected at the centralportions thereof for simultaneous movement and the chamber between thediaphragms being connected for exhaust or bleed to a lower pressure zonesuch as the atmosphere. In such a circuit,-

on one of the diaphragms, fluid at a variable pressure is effective,and, on the other diaphragm, fluid under pressure from a source iseffective, the pressure on the latter diaphragm being controlled by avalve actuated by the movement of the diaphragms. With such a circuit, avalve is also customarily provided for controlling the delivery of fluidto the chamber between the diaphragms for exhaust. The diaphragms in theprior circuits, each being subjected to a relatively high differentialof pressure, are necessarily of a strength and thickness to sustain thepressure applied thereon. This usually has the effect of materiallyreducing the flexibility of each of the diaphragms, as well as resultingin complications of structure."

In accordance with the present invention, a diaphragm construction isprovided of a unitary character, which is quite flexible, which permitsof the use of lighter diaphragm elements or membranes while maintainingadequate strength, which permits of free flow of the fluid to be dis--charged, which will be inert to the fluids used, which will be free fromany tendency to clog, and which will have numerous other advantageousfeatures:

The nature and characteristic features of the invention will be morereadily understood from the following description, taken in connectionwith the accompanying drawings formin part hereof. in which:

Figure 1 is a top or plan view of a relay provided with a diaphragmassembly in accordance with the present invention, parts being brokenaway to show the details of construction;

Fig. 2 is a vertical central sectional view taken approximately on theline 2-2 of Fig. 1;

Fig. 3 is a fragmentary sectional view, enlarged, taken approximately onthe line 3-3 of Fig. 1;

a 2 Fig. 4 is a horizontal proximately on the line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 3 showing a modi- I fled form of theinvention and;

Fig. 6 is a horizontal section view taken approximately on the line 6-6of Fig. 5.

It should, of course, be understood that the description and drawingsherein are illustrative merely, and that various modifications andchanges may be made in the structure disclosed without departing fromthe spirit of the invention.

Referring more particularly to the drawings, the diaphragm assembly Illin accordance with the present invention and for purposes ofillustration and explanation, is shown applied to a pneumatic relayalthough it will, of course, be understood that it is not restricted touse in the specific manner shown and that it has a variety of otherapplications in connection with other pneumatic control apparatus, suchas-pressure regulators, pilot valves and the like.

The pneumatic relay shown for illustrative purposes, preferably includesan upper casing section H and a lower casing section l2 between whichthe diaphragm assembly 10, in accordance with the present invention, isinterposed and held in position by studs l3. A chamber I4 is provided inthe interior of the upper casing section II and above the diaphragmassembly ill, a pipe l5 being connected thereto for the application inthe chambe ll of fluid at variable pressure.

The lower casing section l2 has a fluid inlet connection [6 for thesupplying to the relay of fluid under pressure and a fluid deliveryconnection I'T. The fluid inlet connection I6 is preferably connected bya passageway [8 to a chamber [9 having a valve seat 2|] at the upperportion thereof and closed at its lower end by a plug 2|. Within thechamber is a valve seating member 22 is provided, mounted on andsecuredto a valve stem '2 3, a spring 24 being interposed between the plug 2!and an abutment plate 25, secured to the stem 23 for urgingthe valveseating member 22 towards the valve seat 20.

A chamber 26 is also provided in the lower casing section l2 above thevalve seat 20 andbelow the diaphragm assembly In and a passageway 21 isprovided extending from the chamber 26 to the delivery connection l1.

The diaphragm assembly l0 preferably comprises a lower flat metallicring 3| and an upper flat metallic ring 30. The rings 30 and 3| may beof the same thickness although the lower ring 3| is preferably madethicker. and one of the rings sectional view taken apsuch as the ring IIis provided preferably across its inner flat face with radiallyextending exhaust slots 32 at a plurality of locations. The outer endsof the slots 32 are preferably enlarged by the provision ofcircumferential slots 33 in both rings.

Above the upper ring 30, a diaphragm membrane member 34 is provided,which may be of any suitable sheet material such as rubber, syntheticrubber, such as neoprene, or any other soft highly flexible fluid tightmaterial. A lower diaphragm member 35, which is preferably of the sametype as the upper diaphragm member 34 is also provided. The diaphragmmembers 34 and 35 may be made thinner or of lighter material than hasheretofore been possible for particular pressures applied thereon forreasons which will presently appear. I

The rings 30 and 3|, by reason of their thickness provide a spacebounded on the upper side by the upper diaphragm member 34 and on thelower side by the lower diaphragm member 35. This space is incommunication with the atmosphere or any other desired lower pressurezone through the exhaust slots 32. The diaphragm members 34 and 35 arespaced and separated by an interposed support which is in e; gagementwith the inner faces of each of the tion 39, in communication with thespace between the diaphragm members 34 and 35. In the modifled form ofthe invention illustrated in Figs. 5 and 6, one of the diaphragmmembers, such as the diaphragm member a, is provided, on the inner facethereof, with a plurality of spaced projections 45 which function asinterposed supports by engagement at a plurality of locations over theinner face of the diaphragm member 34, spaces or passageways 45 thusbeing available between the projections 45.

The mode of operation will now be pointed out.

Fluid under pressure is supplied through the fluid inlet connection l6and the fluid delivery connection I! is connected to the desiredapparatus or instrument (not shown). Fluid at vari-v able pressure iseffective through the pipe IS on the upper face of the diaphragm member34. The pressure effective in the chamber l4 on the upper face of thediaphragm 34 is transferred in part by the fabric spacer layers 33 or bythe projections 45 directly to the lower diaphragm member 35 or 35a. Thepressure effective in the chamber 26 is effective on the lower face ofthe diaphragm member 35 and is transferred in part by the spacer layers35 or by the projections 45 to the upper diaphragm member 34.

diaphragm members 34 and 35 but need not be The resultant of thepressures in the chamber l4 and 26 efl'ects the desired positioning ofthe valve seat member 22 with respect to the valve seat 20 forcontrolling the delivery of pressure fluid past the valve seat 20 inaccordance with the variable pressure in the chamber l4. The resultantpressure is effective for normally maintaining the port 40 closed by itsengagement with the stem portion 39 of the stem 23. The

' pressure in the chamber i4 is thus effective for her 35, andtransmitting or transferring the pressure effective on the lower face ofthe diaphragm member 35 through the support to the diaphragm 34, so thatthe pressure from either or both faces is effective simultaneously onthe diaphragm members 34 and 35. The support is also of a characterwhich will permit of free passage of fluid between the diaphragm members34 and 35, is highly flexible, is adequately resistantto fatigue, isresistant to-crushing 'orother undesired deformatiomand is resistant tocorrosion with the fluids employed. For this purpose one or more layersof open mesh supporting fabric 35 as illustrated in Figs. 1 to 5,inclusive,

is preferably provided. The fabric 36 may be of any desired materialhaving the characteristics required and one suitable materialisscreening made from the synthetic plastic known as Saran,

a copolymer of vinyl and vinylidene chloride. I

Support fabrics made from other synthetic plastic materials, such asnylon, and other materials,

such as glass fibres, catgut and the like could also be employed, solong as they have the required characteristics.

The rings 30 and 3| are preferably cemented or otherwise secured in.assembled relationship,

and the diaphragm members 34 and 35 are prefto be guided and seated. Thevalve seating member 35 has a port 40, controlled by. the stemporpositioning the valve seat member 22 and permitting' fluid to flowpast the valve seat 20 and to the chamber 25 for delivery through thepassageway 21 and the delivery connection ii.

If the variable pressure in the chamber 14 should decrease therebytending to produce an effect where an excessive quantity of fluid orexcessive pressure is available inithe chamber 26, the pressureeffective in the chamber 26 tends to raise the diaphragm-members 35 and34. This permits the valve seat member 22 to move closer to the valveseat 20, and if the unbalance due to the excess pressure or quantity offluid is not relieved-further movement tends to open the port 4!!controlled by the stem portion 29. Fluid is thereby permitted to passthrough the port 40 and into the space between the diaphragm members 35and 34 and pass outwardly for discharge through the slots 32 and 33. Assoon as the excess has been discharged, or upon an increase in thevariable pressure effective in the chamber I 4, the port 40 will againbe positioned with respect 'to the stem portion 39 thereby reducing orcutspace between said membranes.

phragm device comprising a flat ring member having a dischargepassageway therein, flexible diaphragm membranes of thin fluid tightmaterial on each side of said ring member and in engagement with thefaces thereof, and membranes spacing and supporting means for permittingfluid flow disposed between said diaphragm membranes and comprising apervious disc in supporting engagement with said membranes over thefacing areas thereof within the ring member, and means for controllingthe access of fluid to the space between said membranes.

4. In pneumatic control apparatus, a diaphragm device comprising apervious central flexible disc portion bounded on opposed sides by fluidtight portions, and means for controlling the access of fluid to thecentral portion for discharge.

5. In pneumatic control apparatus, a diaphragm device comprising closelyspaced flexible diaphragm members, means for spacing said diaphragmmembers at their outer edges, said means including a dischargepassageway, and a sheet portion of flexible open mesh fabric supportingsaid diaphragm members at a plurality of locations over their facingareas and for permitting the flow of fluid to said passageway, and meansfor controlling the access of fluid to the space between said diaphragmmembers for discharge.

6. In pneumatic control apparatus, a diaphragm device comprising a pairof flexible diaphragm members, closely spaced and separated at theirouter edges and having a discharge opening from the space therebetween,and a disc of pervious material for supporting said diaphragm members ata plurality of closely spaced locations over their facing areas andpermitting the flow of fluid to said discharge opening, and

means for controlling the access of fluid to the space between saiddiaphragm members for discharge.

7. In pneumatic control apparatus, 9. diaphragm device comprisingclosely spaced flexible diaphragm members, a ring member for spacingsaid diaphragm members at their outer edges, said ring member having adischarge opening, and at least one layer of flexible screeninginterposed between said diaphragm members for spacing said diaphragmmembers and permitting the flow offluid to said discharge opening, andmeans for controlling the access of fluid to the space between saiddiaphragm members for discharge through said opening.

8. In pneumatic control apparatus, a diaphragm device comprising closelyspaced flexible diaphragm members, a ring member for spacing saiddiaphragm members at their outer edges, said ring member having adischarge opening and supporting projections on one of said diaphragmmembers for spacing said diaphragm members and permitting the flow offluid to said discharge opening and means for controlling the access offluid to the space between said diaphragm members for discharge throughsaid opening.

COLEMAN B. MOORE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

